The present invention relates to a tape recorder, more particularly to an automatic music selection or automatic tape leader feeding mechanism for a cassette tape recorder.
There have been previously provided two types of such automatic music selecting or tape leader feeding mechanisms for cassette tape recorders. In one type, an additional head for detecting a recording position on a tape is used. In the other type, a reproducing head is also used to perform the detecting function. In the former case, the provision of such a detecting head causes an increased production cost.
In the case where the reproducing head is also used therefor, the music selection mechanism operates as follows. When an operatonal switch of the cassette tape recorder is changed over from a play mode to a music selecting mode position, a head base on which the reproducing head is mounted is moved by about 1 mm to 1.5 mm rearwardly and the recording position is detected by the head, which is still in contact with the tape. At the same time, corresponding to the rearward movement of the head base, various mechanism such as a constant rate tape feeding mechanism, a reel drive, and a brake mechanism are inoperative whereas a fast forwarding and rewinding mechanism is operated so as to fast forward or rewind the tape.
In the above described prior art construction, it is very difficult to directly control the various mechanisms according to the head base movement of about 1 mm to 1.5 mm. Accordingly, in addition to a plunger for the play mode which serves to move the head base to the play position, a large capacity plunger producing the same torque as that of the play plunger is needed for controlling the above described various mechanisms. This leads to complexity of construction with an accompanying high cost. Also, a great amount of electric power is needed therefor.
Recently, there has been provided a cassette tape recorder having an electric mode operation mechanism in which a large capacity play plunger is dispensed with and, instead, a power assist mechanism is used. Such a mechanism will be more specifically described. In such a mechanism, a small capacity compact plunger of an energy-saving type is used to move the mechanical parts to a play position with only a small torque. A reduction gear having a cutaway portion, which is rotated when the compact plunger is activated by use of the same switched electric supply, is engaged with a drive gear fixed to a rotatable shaft coaxially with a flywheel. As a result, a high drive torque is obtained using gear reduction. The head base on which the reproducing head is mounted is advanced to the play position through a cam fixed coaxially with the reduction gear. When the electric supply to the compact plunger is stopped, the cam is returned to thereby move the head base back to the stop position.
With this construction, since the head base is driven using the drive gear, the motion thereof is limited to two types, namely, the head base can be moved from the play position to the stop position and vice versa. During these operations, the flywheel is always rotated. Therefore, it is impossible to stop the head base at the music selecting position between the stop position and the play position.